You should see that the NET light starts flashing.

Press the PWRKEY button and hold for about 1 second.

At this time, the PWR light indicator should light up in red and the NET light should be off.

Connect the CP2102 module to the corresponding serial port 1 (or serial port 2) of the SIM800C and use the USB cable to connect the module to the computer.

Insert the CPRS card into the card slot on the back of the module and connect the LTE antenna (The LTE antenna must be rotated to the outside of the board).

A serial module (TTL to USB like CP2102 USB UART Board).

In addition to the micro USB cable and GSM/Bluetooth antenna, users need to prepare the following before using the SIM800C module. When power is on, you can reset the module by pulling down the reset pin. this pin defaults to high and keeps low for 120ms when URCs are reported or SMS received.

High: Sleep Low: Wake-up (should set AT+CSCLK=1) Compliant to Bluetooth specification3.0 + EDR.Supports PAP (Password Authentication Protocol) for PPP connection.GPRS multi-slot class 1~12 (configurable).Comes with development resources and manual (examples for Raspberry Pi/Arduino/STM32).Supports SIM application toolkit: GSM 11.14 Release 99.Control via AT commands (3GPP TS 27.007, 27.005, and SIMCOM enhanced AT Commands).Baudrate auto detection (1200bps ~115200bps).2 x LEDs for indicating the module working status.Bluetooth 3.0, supports data transferring through Bluetooth.Supports SMS, GPRS, DTMF, HTTP, FTP, MMS, email, etc.Compatible with Raspberry Pi 2B/3B/3B+/Zero/Zero W.GSM/GPRS HAT for Raspberry Pi, Based on SIM800C. 3.2 Jetson Nano Minicom Serial Debugging.

Gprs multislot class 1 45